<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="../vue.2.5.1.js"></script>
</head>

<body>
    <div id="app">
        <p>总数：{{total}}</p>
        <my-component @increase='hanleGetTotal' @reduce='hanleGetTotal'></my-component>
    </div>
    <script>
        Vue.component('my-component', {
            template: '<div><button @click="handleCrease">+1</button><button @click="handleReduce">-1</button></div>',
            data() {
                return {
                    counter: 0
                }
            },
            methods: {
                handleCrease() {
                    console.log(11);
                    this.counter++;
                    this.$emit('increase', this.counter);
                },
                handleReduce() {
                    this.counter--;
                    this.$emit('reduce', this.counter);
                }
            }   
        });
        var app = new Vue({
            el: '#app',
            data: {
                total: 0
            },
            methods: {
                hanleGetTotal(total) {
                    this.total = total;
                }
            }
        })
    </script>
</body>

</html>